The present invention relates to a rotary scroll of scroll compressors used in professional and home use refrigerators/air conditioners, and method of manufacturing the rotary scroll.
In a conventional near net material for the rotary scroll comprising a spiral fin on one surface and an axis on the other surface of a base plate, and, as the case may be, a groove for driving, viz. key groove, disposed on a same surface as the axis, a same amount of cutting margin has been provided for each of the parts, as shown in FIG. 8(a) and FIG. 8(b); a cutting margin 4 for spiral fin 3, a cutting margin 5 for axis 2 and a cutting margin 13 for groove 12 having a same amount.
However, with the above described conventional arrangement of cutting margins, viz. a near net material provided with cutting margins of same amount for spiral fin 3 and axis 2, in a case where the cutting margins are determined small intending to reduce machining time for processing the fin part of spiral fin 3, the machining difficulty of which part is high, displacement due to the level of die accuracy, gap between the upper and lower dies, error in the machines used for machining processes, shift of the fiducial, etc. may cause skin of the near net material stay in a place of finished component where it is not admitted, which renders the component unusable. On the other hand, when the cutting margins are determined large, it takes much time to process the spiral fin 3, the machining difficulty of which part is high. Thus, it was difficult to present inexpensive rotary scrolls, hence, inexpensive scroll compressors.